When reading, during the day I like black on white. At night I like white on black.
It depends what terms we're speaking in because even though I like both, I think white letters on black is a lot less professional. You wouldn't hand in your work like that.
If it's for something like your profile, then it doesn't matter.
I find black on white looks more appealing and professional, but it also is better for my eyes! ^^
All is even! XD
25% all round (20/2/17)